This invention relates to the art of pipeline pigs or pipeline packers. Pipeline pigs are used in isolating a predetermined section of a pipeline from the fluid of the pipeline in order to enable repairs, connecting or other maintenance or installation tasks which cannot be done while the medium flows through the respective pipeline.
Various types of pipeline pigs are known in the art. One of the required features of the pipelines is that they be provided with suitable gripping means which would firmly engage the inside wall of a pipeline. To this end, a number of different mechanisms is known utilizing hydraulic power combined with a toggle mechanism and many other ways of securing a firm engagement. Viewed from the standpoint of the present invention, the known pipeline pigs are of complex structure and require additional sources of power for achieving different operational states.
It is an object of the present invention to advance the art by providing a relatively simple structure of a pipeline pig which is capable of being displaced along and locked inside a pipeline solely by utilizing the flow and pressure differentials of the medium inside the pipeline.